This application is related to U.S. Ser. No. 08/022,107 filed on even date herewith.
The present invention relates to a manual transmission of a motor vehicle, comprising a plurality of transmission gears, including forward and reverse gears, which can be shifted with synchronizer clutches.
In the book "Mechanical Transmissions", by Johannes Loomann, Springer-Verlag Berlin, 1998, Page 10, auxiliary transmissions are described which represent a usually two-speed range transmission which is connected in front of or behind the normal manual transmission. These range transmissions have the purpose of increasing the number of gears and the gearing range of the transmission by the multiple use of gearwheel sets. It is stated in this book that, in the case of an interaction with an auxiliary transmission, gearing ratios .rho. in all steps must be approximately identical, in other words, they must form a geometrical row in order to avoid irregularly alternating large and small gearing ratios.
An object of the invention is to provide a manual transmission comprising an auxiliary transmission which, deviating from the geometrical grading, results in a gear grading .rho. which increases in the direction of the lower gears.
This and other objects are achieved by the present invention which provides a manual transmission of a motor vehicle, comprising transmission gears that include a plurality of forward gears and one reverse gear, and synchronizer clutches which shift the gears. All of the transmission gears are arranged such that they can be shifted only by simultaneous closing of two of the synchronizer clutches which are assigned to each gear. The transmission gears are arranged such that a progressive gear grading is provided, with a first range shifting implemented between adjacent transmission gears and a second range shifting implemented between non-adjacent transmission gears.
When a first range shifting is implemented between adjacent gears G1 and G2 and a second range shifting is implemented between the non-adjacent gears G3 and G5, a progressive grading can be achieved which rises in the direction of the lower gears, without the occurrence of irregularly alternating gearing ratios. This progressive grading is desirable in order to achieve a larger spread in the lower gears.
Another important advantage is obtained when, according to an embodiment of the invention, a synchronizer clutch participates in the shifting of all transmission gears. The reason is that, in this case, by means of the uncoupling of the shift rod, which actuates the synchronizer clutch, from an actuating roller, a shifting into idling can take place from any shifted transmission gear. When a roller shifting system is used that is known particularly in the case of motorcycles, not all of the gears must then be shifted through successively in order to arrive in idling, but the idling position can be reached by means of a one-time shifting. Inversely, a shifting into any gear can take place directly from the idling position.
When the gear ratios are selected according to certain embodiments of the invention, a progressive transmission grading and a desired higher spread of the lower transmission gears can be achieved than is possible in the case of the conventional geometrical grading.